Field of the Invention
The present invention relates to an apparatus and a method for broadcasting a stereoscopic 3D video, and more specifically, to a technique to processing speed and time for acquiring a high-quality 3D video by lowering complexity of a reception symbol vector log likelihood ration (LLR) operation in an iterative channel decoding process for acquiring the high-quality 3D video using a hierarchical IL-FEC method.
Description of the Related Art
In a wireless broadcasting system, reception quality of various receivers distributed in a wide range may be significantly various. For example, some applications tend to be received by mobile receivers and fixed receivers. Further, it is sometimes preferable to perform a local service insertion (LSI) inserting local content into some cells without influencing national content during broadcasting. A hierarchical modulation adopted as a broadcasting standard such as Digital Video Broadcasting-Terrestrial (DVB-T) and Digital Video Broadcasting-Next Generation Handheld (DVB-NGH) may be used in applications transmitting two bits as the same signal.
For example, the hierarchical modulation may be used for transmitting content having various definitions such as standard definition (SD), high definition (HD), or ultra-high definition (UHD). The high-definition content is transmitted by mapping high priority (HP) bits and low priority (LP) bits and modulating a hierarchical 16 QAM.
In this case, the broadcasting standard defines a plurality of hierarchical values α and a service provider may select a value suitable for the provided application from the hierarchical values α. For example, the DVB-T allows a service provider to select the value α of 1, 2, or 4, while the DVB-NGH allows the service provider to select the value α of 1, 2, 3, or 4. The value α affects an inter-stream interference level and affects a trade-off between throughput gain and degradation of performance. Typically, a set of hierarchical values α is provided to each application in use. The hierarchical value α is an important element for acquiring a high-quality 3D video and it is necessary to acquire the hierarchical value α suitable thereto.
In a process of de-mapping a symbol vector received from a destination node receiving the hierarchical-modulated symbol vector on the basis of the appropriate hierarchical value α for iterative channel decoding, there is a disadvantage in that the LLR operation complexity of each of the HP stream and the LP bit is large.
As a result, the applicant of the present invention proposes a method for reducing the processing time and speed of the iterative channel decoding at the rear end by reducing the LLR operation complexity of each of the HP stream and the LP bit.